1644439252 has 6 divisors (see below), whose sum is σ = 2877768698. Its totient is φ = 822219624.

The previous prime is 1644439249. The next prime is 1644439253. The reversal of 1644439252 is 2529344461.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1609935376 + 34503876 = 40124^2 + 5874^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1644439253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 205554903 + ... + 205554910.

Almost surely, 2^1644439252 is an apocalyptic number.

It is an amenable number.

1644439252 is a deficient number, since it is larger than the sum of its proper divisors (1233329446).

1644439252 is a wasteful number, since it uses less digits than its factorization.

1644439252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 411109817 (or 411109815 counting only the distinct ones).

The product of its digits is 207360, while the sum is 40.

The square root of 1644439252 is about 40551.6861794920. The cubic root of 1644439252 is about 1180.3367926894.

It can be divided in two parts, 16444 and 39252, that added together give a square (55696 = 236²).

The spelling of 1644439252 in words is "one billion, six hundred forty-four million, four hundred thirty-nine thousand, two hundred fifty-two".